86577457 Performance Upgrade

What exactly is 86577457 engine performance "Envelope Package"?
Ordered one from our local ADI for a sold vehicle, they are out of stock. Is this a USB, software download from TAC? Just wondering if anyone else has ordered this.
Ordered one from our local ADI for a sold vehicle, they are out of stock. Is this a USB, software download from TAC? Just wondering if anyone else has ordered this.